U.S. patent application number 10/707164 was filed with the patent office on 2005-03-24 for [integrated circuit and method for simulating and trimming thereof].
Invention is credited to Chien, Cheng-Hsing, Sung, Yu-Yu.
Application Number | 20050065761 10/707164 |
Document ID | / |
Family ID | 34076604 |
Filed Date | 2005-03-24 |
United States Patent
Application |
20050065761 |
Kind Code |
A1 |
Chien, Cheng-Hsing ; et
al. |
March 24, 2005 |
[INTEGRATED CIRCUIT AND METHOD FOR SIMULATING AND TRIMMING
THEREOF]
Abstract
An integrated circuit and method for simulating and trimming the
same are provided. The integrated circuit includes a multiplexer, a
trimming circuit, a major circuit, and a simulating device. The
simulating device simulates the operation of the trimming circuit
and sends a simulating signal to temporarily change the electric
characteristics. Hence, the electric characteristics of the
integrated circuit after trimming can be predicted so that the
difference between the predicted and real electric characteristics
can be reduced and the yield rate can be effectively improved.
Inventors: |
Chien, Cheng-Hsing; (Hsinchu
County, TW) ; Sung, Yu-Yu; (Hsinchu, TW) |
Correspondence
Address: |
JIANQ CHYUN INTELLECTUAL PROPERTY OFFICE
7 FLOOR-1, NO. 100
ROOSEVELT ROAD, SECTION 2
TAIPEI
100
TW
|
Family ID: |
34076604 |
Appl. No.: |
10/707164 |
Filed: |
November 25, 2003 |
Current U.S.
Class: |
703/14 |
Current CPC
Class: |
G11C 2029/5002 20130101;
G11C 29/028 20130101; G11C 29/54 20130101; G11C 29/50 20130101 |
Class at
Publication: |
703/014 |
International
Class: |
G06F 017/50 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 19, 2003 |
TW |
92125864 |
Claims
1. An integrated circuit comprising: a major circuit providing a
major function; a trimming circuit being trimmable for adjusting
and fixing an electric characteristic of said integrated circuit; a
simulating device simulating an operation of said trimming circuit
and sending out a simulating signal to temporarily change said
electric characteristic of said integrated circuit; and a
multiplexer having an output terminal, a plurality of input
terminals, and a selection terminal, said output terminal being
coupled to said major circuit, said plurality of input terminals
being coupled to said trimming circuit and said simulating
device.
2. The circuit of claim 1, wherein said selection terminal of said
multiplexer receives a selection signal to select one of said
simulating device and said trimming circuit to connect said major
circuit.
3. The circuit of claim 2, wherein when performing a simulating
operation, said multiplexer connects said simulating device to said
major circuit in response to said selection signal, and said
simulating device sends out said simulating signal based on said
electric characteristic of said integrated circuit.
4. The circuit of claim 3, wherein said simulating signal is sent
to said major circuit to temporarily change said electric
characteristic of said integrated circuit.
5. The circuit of claim 2, wherein when performing a trimming
operation, said multiplexer connects said trimming circuit to said
major circuit in response to said selection signal.
6. The circuit of claim 5, wherein when performing said trimming
operation, said trimming circuit is trimmed based on said electric
characteristic of said integrated circuit, said electric
characteristic of said integrated circuit being fixed after said
trimming operation.
7. An integrated circuit, said integrated circuit being simulated
and trimmed in a testing system, said testing system including a
testing device and a simulating device, said integrated circuit
comprising: a major circuit, coupled to said test device, providing
a major function; a trimming circuit being trimmed for adjusting
and fixing an electric characteristic of said integrated circuit;
and a multiplexer having an output terminal, a plurality of input
terminals, and a selection terminal, said output terminal being
coupled to said major circuit, said plurality of input terminals
being coupled to said trimming circuit and said simulating
device.
8. The circuit of claim 7, wherein said selection terminal of said
multiplexer receives a selection signal to select one of said
simulating device and said trimming circuit to connect said major
circuit.
9. The circuit of claim 8, wherein when performing a simulating
operation, said multiplexer connects said simulating device to said
major circuit in response to said selection signal.
10. The circuit of claim 9, wherein when performing said simulating
operation, said testing device detects said electric characteristic
of said integrated circuit and obtains a trimming parameter.
11. The circuit of claim 10, wherein said simulating device sends a
simulating signal to said major circuit based on said trimming
parameter to temporarily change said electric characteristic of
said integrated circuit.
12. The circuit of claim 8, wherein when performing a trimming
operation, said multiplexer connects said trimming circuit to said
major circuit in response to said selection signal in order to trim
said trimming circuit and to change and fix said electric
characteristic of said integrated circuit.
13. A method for simulating and trimming an integrated circuit,
comprising: detecting an electric characteristic of said integrated
circuit; obtaining a trimming parameter based on said electric
characteristic of said integrated circuit; simulating a trimming
operation to adjust said electric characteristic of said integrated
circuit so that said electric characteristic of said integrated
circuit is within an allowable range; and trimming said integrated
circuit based on said trimming parameter.
14. The method of claim 13, wherein said integrated circuit
includes a multiplexer, a trimming circuit, and a major circuit,
said step of simulating a trimming operation comprising: said
multiplexer connecting said major circuit and a simulating device;
said simulating device sending out a simulating signal based on
said trimming parameter; detecting said electric characteristic of
said integrated circuit; determining whether said electric
characteristic of said integrated circuit meets a requirement; and
adjusting said trimming parameter based on said electric
characteristic of said integrated circuit if said electric
characteristic of said integrated circuit does not meet said
requirement, and going back to said step of said simulating device
sending out a simulating signal based on said trimming
parameter.
15. The method of claim 13 further comprising trimming said
integrated circuit based on said rimming parameter without
performing said step of simulating said trimming operation if said
step of simulating said trimming operation is not desired.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority benefit of Taiwan
application serial no. 92125864, filed on Sep. 19, 2003.
BACKGROUND OF INVENTION
[0002] 1. Field of the Invention
[0003] This invention generally relates to an integrated circuit,
and more particularly to an integrated circuit and method for
simulating and trimming thereof.
[0004] 2. Description of Related Art
[0005] The electric characteristics of an integrated circuit will
drift due to the fluctuation of fabrication process. For example,
for an expected output voltage of 1.2 V, the practical output
voltage may range between 1.25V and 1.15 V. This drifting of the
electric characteristic causes uncertainty during the design stage.
To prevent the undesired drifting of the electric characteristic,
one can trim the electric characteristic in order to obtain the
desired result.
[0006] There are two common trimming technologies poly fuse and
laser cut. For the poly fuse trimming, the major part of the
integrated circuit is coupled to a trimming circuit. The trimming
circuit uses polysilicon for connections. To adjust the electric
characteristic, a large current is applied to burn the polysilicon
in order to change the electric characteristic of the integrated
circuit. The laser cut trimming is similar to the poly fuse
trimming. The difference is that metal is used instead of
polysilicon and that the laser is applied to burn the metal rather
than the current.
[0007] FIG. 1 is a block diagram of a conventional integrated
circuit with a trimming circuit. The testing device 110 is coupled
to the integrated circuit 120 to test the electric characteristics
of the integrated circuit 120. The integrated circuit 120 includes
a major circuit 121 and a trimming circuit 122. The major circuit
121 and the trimming circuit 122 are coupled together. FIG. 2 is a
flow chart for illustrating the process flow for trimming the
electric characteristics of an integrated circuit. When trimming
the electric characteristics of the integrated circuit 120, the
testing device 110 tests the electric characteristics of the
integrated circuit 120 (S101). Then, a trimming parameter is
obtained for the integrated circuit 120 (S102). Then a laser or a
current is applied to trim the circuit structure of the trimming
circuit 122 based on the trimming parameter in order to change the
electric characteristics of the integrated circuit 120 (S103).
Finally, the testing device tests the electric characteristics of
the trimmed integrated circuit 120 (S104).
[0008] The drawback of the conventional trimming technique is that
the engineers can only rely on their experience to predict the
electric characteristics of the trimmed integrated circuit. If the
prediction is wrong, the trimmed integrated circuit cannot be used,
which causes a lower yield rate and increases the costs.
SUMMARY OF INVENTION
[0009] An object of the present invention is to provide an
integrated circuit and methods for simulating and trimming. In
accordance to the present invention, the result of the electric
characteristics of the trimmed integrated circuit can be simulated
so that the electric characteristics of the trimmed integrated
circuit can be predicted thereby to reduce the unnecessary costs
and time.
[0010] The present invention provides an integrated circuit
comprising: a major circuit providing a major function; a trimming
circuit being trimmed for adjusting and fixing an electric
characteristic of the integrated circuit; a simulating device
simulating the operation of the trimming circuit and sending out a
simulating signal to temporarily change the electric characteristic
of the integrated circuit; and a multiplexer having an output
terminal, a plurality of input terminals, and a selection terminal,
the output terminal being coupled to the major circuit, the
plurality of input terminals being coupled to the trimming circuit
and the simulating device. The selection terminal of the
multiplexer receives a selection signal to select one of the
simulating device and the trimming circuit to connect the major
circuit.
[0011] In the first embodiment of the present invention, when
performing a simulation operation, the multiplexer connects the
simulating device to the major circuit in response to the selection
signal. A testing device then tests the electrical characteristic
of the integrated circuit and determines a trimming parameter
according to the electrical characteristic. The parameter is then
sent to the simulating device and the simulating device sends out
the simulating signal based on the electric characteristic of the
major circuit. The simulating signal is sent to the major circuit
to temporarily change the electric characteristic of the integrated
circuit. When performing a trimming operation, the multiplexer
connects the trimming circuit to the major circuit in response to
the selection signal. When performing the trimming operation, the
trimming circuit is trimmed based on the electric characteristic of
the integrated circuit. The electric characteristic of the
integrated circuit is fixed after the trimming operation.
[0012] Another aspect of the present invention provides an
integrated circuit, the integrated circuit being simulated and
trimmed in a testing system, the testing system including a testing
device and a simulating device, the integrated circuit comprising:
a major circuit, coupled to the test device, providing a major
function; a trimming circuit being trimmed for adjusting and fixing
an electric characteristic of the integrated circuit; and a
multiplexer having an output terminal, a plurality of input
terminals, and a selection terminal, the output terminal being
coupled to the major circuit, the plurality of input terminals
being coupled to the trimming circuit and the simulating
device.
[0013] In the second embodiment of the present invention, the
selection terminal of the multiplexer receives a selection signal
to select one of the simulating device and the trimming circuit to
connect the major circuit. When performing a simulating operation,
the multiplexer connects the simulating device to the major circuit
in response to the selection signal. When performing the simulating
operation, the testing device detects the electric characteristic
of the integrated circuit and obtains a trimming parameter. The
simulating device sends a simulating signal to the major circuit
based on the trimming parameter to temporarily change the electric
characteristic of the integrated circuit. When performing a
trimming operation, the multiplexer connects the trimming circuit
to the major circuit in response to the selection signal in order
to trim the trimming circuit and to change and fix the electric
characteristic of the integrated circuit.
[0014] The present invention provides a method for simulating and
trimming an integrated circuit, comprising: detecting an electric
characteristic of the integrated circuit; obtaining a trimming
parameter based on the electric characteristic of the integrated
circuit; simulating a trimming operation to adjust the electric
characteristic of the integrated circuit so that the electric
characteristic of the integrated circuit is within an allowable
range; and trimming the integrated circuit based on the rimming
parameter.
[0015] In a preferred embodiment of the present invention, the
integrated circuit includes a multiplexer, a trimming circuit, and
a major circuit, the step of simulating a trimming operation
comprising: the multiplexer connecting the major circuit and a
simulating device; the simulating device sending out a simulating
signal based on the trimming parameter; detecting the electric
characteristic of the integrated circuit; determining whether the
electric characteristic of the integrated circuit meets a
requirement; and adjusting the trimming parameter based on the
electric characteristic of the integrated circuit if the electric
characteristic of the integrated circuit does not meet the
requirement, and going back to the step of sending out a simulating
signal by the simulating device based on the trimming
parameter.
[0016] The present invention uses a multiplexer in the conventional
integrated circuit so that the major circuit can be
switch-connected. The present invention also uses a simulating
device to simulate the conventional trimming circuit and to send
out a simulating signal to temporarily change the electric
characteristics of the integrated circuit. Hence, the electric
characteristics of the trimmed integrated circuit can be predicted
to see if the electric characteristics can meet the requirement,
thereby reducing any unnecessary costs and time.
[0017] The above is a brief description of some deficiencies in the
prior art and advantages of the present invention. Other features,
advantages and embodiments of the invention will be apparent to
those skilled in the art from the following description,
accompanying drawings and appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 is a block diagram of a conventional trimming
integrated circuit.
[0019] FIG. 2 is a flow chart illustrating the flow of a
conventional trimming process on the electric characteristics of an
integrated circuit.
[0020] FIG. 3 is the block diagram of an integrated circuit with
simulating and trimming functions in accordance with the first
embodiment of the present invention.
[0021] FIG. 4 is the block diagram of an integrated circuit with
simulating and trimming functions in accordance with the second
embodiment of the present invention.
[0022] FIG. 5 is the flow chart for simulating and trimming the
electric characteristics of the integrated circuit in accordance
with a preferred embodiment of the present invention.
DETAILED DESCRIPTION
[0023] FIG. 3 is the block diagram of an integrated circuit with
simulating and trimming functions in accordance with the first
embodiment of the present invention. The present invention provides
an integrated circuit 220, wherein trimming can be simulated in the
testing system, The testing system includes a testing device 210
and a simulating device 230. The testing device is coupled to said
integrated circuit 220 and the simulating device 230.
[0024] The integrated circuit 220 includes a multiplexer 222, a
trimming circuit 223, and a major circuit 221. The multiplexer 222
has an output terminal, a plurality of input terminals, and a
selection terminal. The output terminal is coupled to the major
circuit 221; the plurality of input terminals is coupled to the
trimming circuit 223 and the simulating device 230. The selection
terminal sel of the multiplexer receives a selection signal to
select one of the simulating device and the trimming circuit to
connect the major circuit. The trimming circuit 223 includes a
trimmable circuit for adjusting and fixing the electric
characteristic of the integrated circuit 220. The simulating device
230 simulates the operation of the trimming circuit 223 and sends
out a simulating signal to temporarily change the electric
characteristic of the integrated circuit 220.
[0025] FIG. 5 is the flow chart for simulating and trimming the
electric characteristics of the integrated circuit in accordance
with a preferred embodiment of the present invention. When the
testing device 210 detects the electric characteristic of the
integrated circuit 220 (S210), a trimming parameter is obtained
based on the electric characteristic of the integrated circuit by
looking up a table (S220). For example, if the desired output
voltage is 1.2V but the detected output voltage is 1.25V, the
look-up table will provide a trimming parameter. When performing a
simulation, the steps shown in S240 of FIG. 5 will be performed.
When perform a trimming operation without a simulation, the
multiplexer 222 will connect the major circuit 221 and the trimming
circuit 223 (S250). Then a laser or current will be applied to trim
the trimming circuit 223 based on the trimming parameter (S260).
Finally, the electric characteristic of the integrated circuit
after trimming will be detected (S270), which is a fixed value.
[0026] When performing a simulation, the multiplexer 222 connects
the major circuit 221 and the simulating device 230 (S241), and the
simulating device 230 sends out a simulating signal based on the
trimming parameter to temporarily change the electric
characteristic of the integrated circuit 220 (S242). The electric
characteristic of the integrated circuit is then detected again
(S243), and whether the electric characteristic of the integrated
circuit meets a requirement (S244) is determined. If the electric
characteristic of the integrated circuit does not meet the
requirement, the trimming parameter will be adjusted based on the
electric characteristic of the integrated circuit (S245) and the
flow resumes to step S242.
[0027] FIG. 4 is the block diagram of an integrated circuit with
simulating and trimming functions in accordance with the second
embodiment of the present invention.
[0028] The integrated circuit 240 includes a multiplexer 242, a
trimming circuit 243, and a major circuit 241, and a simulating
device 244. The multiplexer 242 includes an output terminal, a
plurality of input terminals, and a selection terminal. The output
terminal is coupled to the major circuit 241, while the plurality
of input terminals is coupled to the trimming circuit 243 and the
simulating device 244. The selection terminal sel of the
multiplexer receives a selection signal to select one of the
simulating device 244 and the trimming circuit 243 to connect the
major circuit 241. The trimming circuit 243 includes a circuit that
can be trimmed for adjusting and fixing the electric characteristic
of the integrated circuit 240. The simulating device 244 simulates
the operation of the trimming circuit 243 and sends out a
simulating signal to temporarily change the electric characteristic
of the integrated circuit 240. The second embodiment is performed
in a same way as the first embodiment, and hence will not be
further described here.
[0029] In light of above two embodiments, the simulating device can
simulate the operation of the trimming circuit and send a
simulating signal to temporarily change the electric
characteristics. Hence, the electric characteristics of the
integrated circuit after trimming can be predicted so that the
difference between the predicted and real electric characteristics
can be reduced and the yield rate can be effectively improved.
[0030] The above description provides a full and complete
description of the preferred embodiments of the present invention.
Various modifications, alternate construction, and equivalent may
be made by those skilled in the art without changing the scope or
spirit of the invention. Accordingly, the above description and
illustrations should not be construed as limiting the scope of the
invention which is defined by the following claims.
* * * * *